ASP.NET Core MVC应用程序中的后台工作任务

C#

浏览数:134

2019-7-2

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  在应用程序的内存中缓存常见数据(如查找)可以显着提高您的MVC Web应用程序性能和响应时间。当然,这些数据必须定期刷新。

  当然你可以使用任何方法来更新数据,例如Redis中就提供了设定缓存对象的生命时间,那么对于这种单对象的更新的做法我觉得是不符合我的编程习惯的,我们可以使用QuartZ.NET 框架来进行任务调度,我们在任务计划中进行统一的缓存更新,也就达到了我们的目的。

  Quartz受到良好支持,跨平台库可用于在应用程序内部调度任务。由于ASP.NET Core架构和开箱即用的中间件支持,在.NET Core MVC Web应用程序中使用它有点不同。在本文中,我将尝试使用ASP.NET核心应用程序中的Quartz来解释后台工作者计划任务的简单计划。

  我使用简单的ASP.NET Core WebApi项目模板作为示例项目的基础。由于我们不会关注端点的实际响应,而是关注Startup.cs依赖注入部分和中间件,默认的WebApi项目模板就好了。

  作为第一步我们应该引用Quartz框架,我将使用Nuget管理器,我现在使用的工具是Visual Studio 2019 体验版。

Install-Package Quartz -Version 3.0.7

  如果你在Linux或Mac Os上进行开发,那么请安装.net core sdk 在使用.net 脚手架来进行引入。

dotnet add package Quartz --version 3.0.7

  由于ASP.NET Core具有开箱即用的依赖注入支持,我们需要在启动时设置我们的解析器,但在我们这样做之前,我们需要编写我们将用于设置调度的一些Quartz接口的实现我们项目中的任务。

  我们首先需要编写我们的任务,即将按特定时间表执行的代码单元。为此,我们需要在我们的作业类中实现  Quartz.IJob接口。

using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Logging;
using Quartz;
using System;
using System.Threading.Tasks;

namespace Schedule.WebApiCore.Sample.Schedule
{
    public class ScheduledJob : IJob
    {
        private readonly IConfiguration configuration;
        private readonly ILogger<ScheduledJob> logger;


        public ScheduledJob(IConfiguration configuration, ILogger<ScheduledJob> logger)
        {
            this.logger = logger;
            this.configuration = configuration;
        }

        public async Task Execute(IJobExecutionContext context)
        {

            this.logger.LogWarning($"Hello from scheduled task {DateTime.Now.ToLongTimeString()}");

            await Task.CompletedTask;
            
        }
    }
}

由于它只是一个示例应用程序,因此每次作业执行时,我只会在输出中写入当前时间的消息。将从Startup.cs类方法注入Microsoft.Extensions.Configuration.IConfiguration和Microsoft.Extensions.Logging.ILogger接口实现的实例

我们需要实现的下一个接口是Quartz.Spi.IjobFactory。

using Quartz;
using Quartz.Spi;
using System;

namespace Schedule.WebApiCore.Sample.Schedule
{
    public class ScheduledJobFactory : IJobFactory
    {
        private readonly IServiceProvider serviceProvider;

        public ScheduledJobFactory(IServiceProvider serviceProvider)
        {
            this.serviceProvider = serviceProvider;
        }

        public IJob NewJob(TriggerFiredBundle bundle, IScheduler scheduler)
        {
            return serviceProvider.GetService(typeof(IJob)) as IJob;
        }

        public void ReturnJob(IJob job) {
            var disposable = job as IDisposable;
            if (disposable != null)
            {
                disposable.Dispose();
            }
        }
        
    }
}

   我们将IJobFactory接口实现的实例分配给我们的IScheduler实例,该实例将用于在每个调度触发器上实例化作业实例。现在在我们的Startup.cs中设置依赖注入解析器。

配置

using System;
using System.IO;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Quartz;
using Quartz.Impl;
using Quartz.Spi;
using Schedule.WebApiCore.Sample.Schedule;


namespace Schedule.WebApiCore.Sample
{
    public class Startup
    {

        public IConfiguration Configuration { get; }
        public IHostingEnvironment HostingEnvironment { get; }

        public Startup(IConfiguration configuration, IHostingEnvironment hostingEnvironment)
        {
            this.HostingEnvironment = hostingEnvironment;
            this.Configuration = configuration;
        }

        public void ConfigureServices(IServiceCollection services)
        {
            services.AddLogging();

            services.AddSingleton<IConfiguration>(new ConfigurationBuilder()
                .SetBasePath(Directory.GetCurrentDirectory())
                .AddJsonFile("appsettings.json")
                .AddJsonFile($"appsettings.{this.HostingEnvironment.EnvironmentName.ToLower()}.json")
                .Build());

            #region Configure Quartz DI

            services.Add(new ServiceDescriptor(typeof(IJob), typeof(ScheduledJob), ServiceLifetime.Transient));
            services.AddSingleton<IJobFactory, ScheduledJobFactory>();
            services.AddSingleton<IJobDetail>(provider =>
            {
                return JobBuilder.Create<ScheduledJob>()
                  .WithIdentity("Sample.job", "group1")
                  .Build();
            });

            services.AddSingleton<ITrigger>(provider =>
            {
                return TriggerBuilder.Create()
                .WithIdentity($"Sample.trigger", "group1")
                .StartNow()
                .WithSimpleSchedule
                 (s =>
                    s.WithInterval(TimeSpan.FromSeconds(5))
                    .RepeatForever()
                 )
                 .Build();
            });

            services.AddSingleton<IScheduler>(provider =>
            {
                var schedulerFactory = new StdSchedulerFactory();
                var scheduler = schedulerFactory.GetScheduler().Result;
                scheduler.JobFactory = provider.GetService<IJobFactory>();
                scheduler.Start();
                return scheduler;
            });

            #endregion


            services.AddMvc();
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IHostingEnvironment env, IScheduler scheduler)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }

            scheduler.ScheduleJob(app.ApplicationServices.GetService<IJobDetail>(), app.ApplicationServices.GetService<ITrigger>());

            app.UseMvc();
        }
    }
}

修改Startup.cs

  启动项目没有什么问题~但当你将所有部件放在Startup.cs中的一个地方时,这样更容易解释整个DI设置,在那里你可以看到所有的依赖关系和接口是如何解决的,但是从长远来看,这个Startup.cs应该是凌乱的它最终将成为维持的噩梦。出于这个原因,我将整个DI包装到扩展方法中。

  综上所述,我们的.Net Core为我们提供了解决方案,那么把Quartz的代码全部放到一个静态类中,它将使用Quartz的Microsoft依赖注入语句和管道的Microsoft.AspNetCore.Builder.IApplicationBuilder扩展  Microsoft.Extensions.DependencyInjection.IServiceCollection 。

  就我个人而言,我喜欢在项目中创建一个Extensions文件夹,然后在其中写入类,再去Startup.cs中进行配置!QuartzExtensions定义如下:

    public static class QuartzExtensions
    {
        public static void AddQuartz(this IServiceCollection services, Type jobType)
        {
            services.Add(new ServiceDescriptor(typeof(IJob), jobType, ServiceLifetime.Transient));
            services.AddSingleton<IJobFactory, ScheduledJobFactory>();
            services.AddSingleton<IJobDetail>(provider =>
            {
                return JobBuilder.Create<ScheduledJob>()
                  .WithIdentity("Sample.job", "group1")
                  .Build();
            });

            services.AddSingleton<ITrigger>(provider =>
            {
                return TriggerBuilder.Create()
                .WithIdentity($"Sample.trigger", "group1")
                .StartNow()
                .WithSimpleSchedule
                 (s =>
                    s.WithInterval(TimeSpan.FromSeconds(5))
                    .RepeatForever()
                 )
                 .Build();
            });

            services.AddSingleton<IScheduler>(provider =>
            {
                var schedulerFactory = new StdSchedulerFactory();
                var scheduler = schedulerFactory.GetScheduler().Result;
                scheduler.JobFactory = provider.GetService<IJobFactory>();
                scheduler.Start();
                return scheduler;
            });

        }

        public static void UseQuartz(this IApplicationBuilder app)
        {
            app.ApplicationServices.GetService<IScheduler>()
                .ScheduleJob(app.ApplicationServices.GetService<IJobDetail>(),
                app.ApplicationServices.GetService<ITrigger>()
                );
        }
    }

现在我们的Startup.cs更清洁,更容易维护和扩展!

    public class Startup
    {
        public IConfiguration Configuration { get; }
        public IHostingEnvironment HostingEnvironment { get; }

        public Startup(IConfiguration configuration, IHostingEnvironment hostingEnvironment)
        {
            this.HostingEnvironment = hostingEnvironment;
            this.Configuration = configuration;
        }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddLogging();

            services.AddSingleton<IConfiguration>(new ConfigurationBuilder()
                .SetBasePath(Directory.GetCurrentDirectory())
                .AddJsonFile("appsettings.json")
                .AddJsonFile($"appsettings.{this.HostingEnvironment.EnvironmentName.ToLower()}.json")
                .Build());

            services.AddQuartz(typeof(ScheduledJob));

            services.AddMvc();
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IHostingEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }

            app.UseQuartz();

            app.UseMvc();
        }
    }

再次启动项目,ok 通过~

 祝.Net Core 越来越好!

作者:张子浩